Sin

For convicting one of sin by the Law, consider, “The heart is deceitful above all things, And desperately wicked; Who can know it? I, the Lord, search the heart, I test the mind, Even to give every man according to his ways, According to the fruit of his doings” (Jeremiah 17:9–10 NKJV). Here the Lord teaches these two things:

First, the source of all our miscarriages and actual sinning against God is in the heart. The [biblical, spiritual] heart includes the mind, will, affections [emotions, feelings], and all the powers of the soul, which powers are corrupted and defiled by original sin. The mind is not only ignorant and incapable of saving truth, but also full of error and enmity against God. The will and affections are obstinately disobedient against all God’s directions and bent toward only that which is evil. “The heart,” says God, “is deceitful above all things, and desperately wicked.” Yes, and unsearchably wicked; thus “Who can know it.” And, “The Lord saw that the wickedness of man was great in the earth, and that every intention of the thoughts of his heart was only evil continually” (Genesis 6:5 ESV), says the Lord, whose testimony we must trust in this and all other matters. And experience also may teach us that, until God makes us deny ourselves, we never look to God in anything; rather fleshly self interest alone rules us and moves all the wheels of our actions.

Second, the Lord brings our original sin (wicked inclinations) and all the actual fruits produced by it into reckoning before His judgment seat,³⁵ for “I the Lord search the heart and test the mind, to give every man according to his ways, according to the fruit of his deeds” (Jeremiah 17:10 ESV).

35 Contrary to what is taught by some, the wicked inclinations that come out of our wicked and deceitful hearts due to original sin are themselves sin and must be repented of. Care and sanctification of our hearts is vital. “Keep your heart with all vigilance, for from it flow the springs of life” (Proverbs 4:23 ESV).